Most semiautomatic handguns include a frame and a slide that moves along the firearm's longitudinal firing axis in a reciprocating manner. The frame provides the core support structure for the firearm's operational and other components, e.g., trigger and firing mechanisms, grip, ammunition feeding system, barrel, and slide. For operably attaching the slide to the frame, the frame includes a set of rails positioned on opposite longitudinal sides of the frame. The rails are integral with the rest of the frame, i.e., the frame, including the rails, is machined or otherwise formed from a single piece of metal or other material.
In addition to the rails, the frame includes other integrally machined features for attaching, supporting, and/or guiding additional components of the firearm such as the trigger and firing mechanism sear. While such features (including the rails) function well from an operational standpoint, the manufacturing process for forming the rails and other integral features can be time consuming and complex.